( See later updates at the end.) The lights appear to be outdoor lights that have been repurposed for underwater use. I am sure they will give long lasting service as landscape lights, but the upper seals on the lights do not appear to be sufficient for underwater use. They are sealed by just a thin, silicone O-ring, and the cap is a snap-lock cap as opposed to a screw top. A snap-lock cap doesn't provide sufficient, uniform, force to maintain the seal. A screw top would give better sealing power. Even better would be a permanently sealed light with colored lenses that go OVER the light's lens, as opposed to the colored filters actually being the lens, as they are in this case. I resealed my lenses with silicone sealer, as I did not trust the seals after reading other buyer's posts. They did not leak after being submerged for 48 hours. The bottoms appear to be well sealed, but, I would caution users not to be rough in their handling of the lights, as the lights are fairly heavy, and I suspect that rough handling, or leaving them dangling could break the seals on the wires. Also, any nick in the insulation of the wires, could potentially cause a leak. The transformer got warm while in use, and I suspect that the transformer may be a bit under powered for 6 lights. It appears that the company has been adding more and more lights, and they may not have upgraded the transformers as they added more lights to the original set. I know the lights came in a box for a three light set, with a "6" sticker placed over the "3" on the box. Time will tell on that.** (see note below) The transformer is also a bit big for use with covered, outdoor outlets, and you may have to use an extension cord or some other method to plug them in. There was also a lack of uniformity in the way the light's position could be adjusted. Some clicked nicely into each position, and some just barely clicked. On the plus side, the lights are bright, but not too bright, giving a pleasant accent light underwater. However, if you like your pond lights very bright, these may not be the ones for you. I also agree with other posters that the red filter makes the lights look pink. The lights are sufficiently heavy to place easily on the bottom of the pond, and the cord length from the plug to the first light was long enough to reach my power source. The price per light was also a selling point for me, as some pond lights are priced ridiculously high. I like the two pronged plug for plugging into the transformer, and I notice that splitters are available, which should allow for the use of multiple sets, if you have a large enough transformer. UPDATE: I purchased and used one of the splitters, and was able to get it to work, but the male prongs and the female holes were not an exact match. However, they did go together with a little coaxing. 5/10/20 UPDATE: I have now been using the lights (2 sets) for well over a year, having originally sealed the lenses with silicone caulk, and I have not had any leak problems. I would also note that even though the lights are fairly heavy, and the mounts do rotate some, they are not very easy to position in the pond exactly where you want the lights to shine. ** Note: I ended up using an old transformer that I already had that had a higher wattage rating, because I did not like the original transformer getting so hot. I haven't had any trouble with the new setup. 3-5-21 Update I have had one light in each set I bought go out. In both cases, it appeared to be water leakage that caused the failures. The first leak, I pulled the light out of the pond and let it dry out. Then I put some rice inside, and resealed the light with silicone caulk and left it out of the pond for about 2 months. Amazingly, it started working again, so I am going to try the same thing on the other light. I'm not sure that silicone caulk is the best sealant to use on these lights. It doesn't seem to adhere to the plastic as well as I would like, and so far it has a 16% failure rate, so I may try FlexSeal on the ones I have to fix in the future. I also just recently noticed that the light array in the fixture plugs in with two pins, so theoretically it can be replaced if it stops working. However, I wouldn't know where to start looking for a replacement array. The pins do look very similar to other two pin lights, so possibly a different bulb or array could suffice, as long as they were LEDs. You could also buy an extra set to use the new arrays for spares, and not have to replace the whole set, when one goes out. Of course, getting a good seal on the lenses is always going to be your big problem.